reference the American Bar Association Model Rule 3.1, which states that a lawyer shall not bring or defend a proceeding, or assert or controvert an issue therein unless there is a basis in law and fact for doing so that is not frivolous, which includes a good faith argument for an extension, modification or reversal of existing law. Explain if there are any differences from Rule 3.1 of the Massachusetts Rules of Professional Conduct, titled "Meritorious Claims and Contentions